将GStrings存储在变量中并在运行时进行计算

Question

我在映射中存储了一些GString，并试图在运行时将其评估为：

//this is in begginning of my class or controller or service and is a global variable
def placeholderStrings=["nameString":"My name is $name","professionString":"My profession is $profession"]
//this params map comes after arrival of request from client side and following code is inside the controller
params=["name":"name1","profession":"profession1"]
def paramsKeyMap=params.keySet()
paramsKeyMap.each{
    bindings."$it"=params[it]
    println it
}
println placeholderStrings.get("nameString") // this line gives error as groovy.lang.MissingPropertyException: No such property: name

上面的代码给出错误，但下面的代码运行：

params=["name":"name1","profession":"profession1"]
def keyMap=params.keySet()
keyMap.each { 
    binding[it] =params[it] 
    println it // or even binding[it] = 'something' 
}
//Now I am declaring it locally pls note this
def placeholderStrings=["nameString":"My name is $name","professionString":"My profession is $profession"]
println placeholderStrings.get("nameString") // this line gives error as groovy.lang.MissingPropertyException: No such property: name

正如我们所看到的区别，在第一个脚本中，占位符字符串是在绑定之前声明的，而在第二个脚本中是在绑定之后声明的。我想做一些类似于第一种情况的事情，因为在我的应用程序中，我需要在运行时根据客户端请求评估占位符字符串。

• 当请求到来时，我需要使用placeholderStrings.get(keyFromParams)获得适当的值
• 替换上面获得的字符串中绑定的占位符

现在的问题是，当我调用placeholderStrings.get(keyFromParams)时，它会尝试替换字符串中的占位符并抛出异常。

为了解决这个问题，我尝试将占位符字符串值存储为单引号字符串，如：

def placeholderStrings=["nameString":'My name is $name',"professionString":'My profession is $profession']

但现在我没有办法将上面映射中的值转换为GString，以便替换占位符。那么，有人能提出可以做些什么吗？

Answer 1

Lazy GStrings（例如"My name is ${-> name}"）可能会解决这个问题，但在脚本绑定中注入替换的整个方法对我来说就像是一个黑客（和潜在的安全漏洞）。使用模板引擎可能会更好。Groovy附带了SimpleTemplateEngine和GStringTemplateEngine，尽管我被告知使用它们很容易遇到内存泄漏问题（我不知道细节）。

Answer 2

使用Expando。

def exp = new Expando()
exp.nameString = {"My name is $name"}
exp.professionString = {"My profession is $profession"}
exp.name = "Rahul"
exp.profession = "SoftwareEngineer"
assert exp.nameString() == 'My name is Rahul'
assert exp.professionString() == 'My profession is SoftwareEngineer'
exp.name = "Sachin"
exp.profession = "Cricket"
assert exp.nameString() == 'My name is Sachin'
assert exp.professionString() == 'My profession is Cricket'

编辑
不使用Expando

def params = [name: 'Rahul', age: 25, profession: 'developer']
def stringMap = params.collectEntries([:]){k, v ->
    def key = k + "String"
    [(key), "My $k is $v"]
}
assert stringMap instanceof java.util.LinkedHashMap
assert stringMap == [nameString:"My name is Rahul", ageString:"My age is 25", professionString:"My profession is developer"]
assert stringMap.nameString == "My name is Rahul"